Fluorescent lamp socket



Sept. 15, 1942. l M, N RUSSELL FLUORESCENT LAMP SOCKET Filed March l, 1941 Patented Sept. 15, 1942 UNETED STATES fr FFECE Seymour, Enc., Solvay Station, Syracuse,

N. Y., a corporation of New York Application March 1, 1941, Serial No. 381,373

l Claims.

This invention relates to lamp sockets and more particularly to sockets for double-ended electric lamps or similar devices, of which the present popular iuorescent lamp is an example, requiring the use of sockets in pairs, the two units of which are spaced apart so as to engage each with at least two contact or terminal pins at its end of a lamp.

It is a general object of the present invention to provide a novel and improved socket structure for certain specific uses.

More particularly it is an object of the invention to provide in a socket for fluorescent lamps and similar devices means for electrically connecting together the two terminal pins on one end of a lamp when it is positioned in the socket, but to open the circuit between the socket contact members, which are engageable with these pins, when the lamp is removed from the socket.

An important featureV of the invention consists in the provision of a bridging contact member adapted for arrangement in the conventional iluorescent lamp socket, which member is normally insulated from the pair of spring contacts therein but serves to electrically connect them together when a lamp is positioned in the socket.

A further important feature of the invention comprises the arrangement of the bridging contact and its insulating means whereby it is adapted for arrangement in the conventional socket.

Other and further features and objects of the invention will be more apparent to those skilled in the art upon a consideration of theaccompanying drawing and following specification wherein is disclosed a single exemplary embodiment ci the invention with the understanding that such changes and modifications may be made therein as fall within theV scope of the appended claims without departing from the spirit of the invention.

In said drawing: l

Figure l is a rear elevation of a lsocket constructed in accordance with the present invention, the insulating rear cover plate being removed to expose the contact assembly;

Figure 2 is a transverse section taken on line 2 2 of Figure l on an enlarged scale and showing the end of lamp associated with the socket and its contacts;

Figure 3 is front view of the socket;

lFigure l is a perspective view on an enlarged scale of the bridging contactv member;

Figure 5 is a perspective view on the same scale as Figure l oi' one oi the insulating elements; and

Figure 6 is a wiring diagram showing a pair of lamps and their associated transformers arranged in a circuit peculiarly adapted for sockets of the present construction.

Fluorescent lamps and similar devices are usually of tubular construction, comprising a body portion formed of cylindrical glass tubing as shown at lll in Figure 2, having a cap at each end as shown at il. This cap insulatingly supports a pair of terminal pins i2 and i 3, parallel to each other and to the axis of the lamp tube and laterally spaced apart. These are, in the usual construction, connected to the two ends of a iilarnent ld just within the end of the lamp. The normal purpose of the filament is to supply heat for starting the lamp after which, through the agency of a suitable starting device, the current is shut off from the filament and it acts solely as a terminal at its end of the lamp, the current between opposite terminals passingthrough the gas in the lamp, ionizing the same and activating the uorescent material with which the walls of the lamp tube are coated.

In the conventional operation of such lamps, various types of starting means are used to enrsure the energization oi the laments momentarily, the application of anshoc'k voltage to break down the resistance of the gas in the tube, and nally the deenergization of the laments. Lamps are normally actuated at a voltage different from the line voltage and this isachieved through the use of transformers, reactances or the like sometimes associated with means to change the lead or lag of the current so that when lamps are operated, as customary, in pairs the power factor is improved and stroboscoplc effects eliminated.

The sockets for use in supporting and con` necting the lamps when used in the manner above described are fully illustrated in thepatent to Marshaus No. 2,137,174 and need not be described in detail here, but by reference to Figures l and 3 it will be seen that they comprise a base or body portion its of suitable insulating material having a recess lo in the back adapted to accommodate a pair of contact springs il and it each having a terminal member it and a clamp screw 2U, these latter'being arranged for access through the open bottom. The springs are spaced. apart by a central web 2l and an 'integral guide stud E2, and shoulders 23 and 2t `serve as abutments for the terminal portions to retain the contacts in position. A cover plate 2t shown only in Figure 2 .closes the back of the socket and holds the contacts therein. 'Wings integral with the 'body each or the bights 2@ of its contact spring and between the same and the stuc'.

0n the exposed tace of the sociset as sho .in Figure 3, these spun-gs appear in the cirn cular recess into ch the central stud 2E projects from the solid baci; .support shown, This post is slotted diarnetrcallyn as at t3 in alignment with slot 2B to permit one pin to pass through the same as the lamp is inserted and to then be rotated into engagement with one oi the springs whilcgthevthcr pin moves 'ueneath the other, spring 'oy the aid o its upturned end 2i. By this construction each Contact pin is electrically connected to one Voi" the contact springs and both. pins are clamped against the central stud by these springs and heid in posin tion to securely support the lamp, which can only be removed by a 90 rotation ot the same about its axis to bring the pins in alignment with the slots .29 and Under a more recently developed system for operating the lamps, the filaments are never used for heating purposes, acting solely as terminals'or cold cathodes one at either end of the lamp. Under these conditions the need for a separate connection to eacli or the pins 'at each end `of the lamp disappears and t ey may be both connected together during starting and while the lamp is in operation. For starting purposes a voltage three to four times as great as the normal 'operating voltage for the lamp is applied between the terminals at opposite ends thereof and serves to break down. the resistance ci the gas in the lamp. rlhis voltage, being much higher than the operating volt age, is dangerous and the underwriters require that when the lamps are removed from the socket, the source of this high voltage be dire1 connected from the main power line normally `provides alternating current at lle volta it is a purpose oi the present invention 'w so improve the sockets that the pair of pins at each end of the lamp will be connected together by the socket associated therewith, the spring contacts oi the vsoclret will not be connected together when the lamp is removed, to thereby open the circuit to the source ci high voltage. The are rangement is as shown in Figure c where the four coils it, di, t2, and i3 are arranged in asingle housing and constitute respectively the two priw maries and two secondaries of a transformer. The primaries are connected in parallel as shown and also to a source of alternating current at ftd, one or the conductors dii passing through two of the sockets in accordance with the Ipresent invertis tion before being connected to the junction of the two primaries. When the lamps are removed it will be seen that the circuit will be opened in two places in wire di). Since the terminals 2@ oany one lamp socket are insulated from each other by the body thereof the circuit will be open eX- cept when the lamps are in. position as will be later described. Each secondary has its: open end connected to one of the opposite ends of one of the lamps as by the conductors it and el while the other ends of the secondaries are connected face of the body as seen. in Figura. -inrier edges project inwardly so as to i; i

. the recess iiA Each of the arms `lation characteristics o the transiorme"4 out the above operation comprises a sin connected together at their inner er together at iti and to the conductor iea' from the source of power to the june o set of ends the that when the current is :first tu of approximately 400 is appiied l postte ends of the lamps, the ating on the auto-transforme primary and one secondary in se s lamp, whereas the power source s'ap the primaries constituting total winding. The high voir-Ue across the resistances of the lamp tu creased and the higher flow of curren.: the potential across the lamps to that for their operation and somewhat iess potential at Lii. This results from the p operation the laments are not heatev acts only as a terminal at its end oi the iarur; for starting and running,

To ensure proper operation even thou or more of the filaments of the la burned out; to ensure that no currar through intact laments to heat i provide a closed primary circuit ci lamps are in the sockets, an auxiii Contact is provided in each socia@ and shuntsthe two pins ci the cc end of the lamp when they in pos thus there is no circuit through the ends of the filaments at the 1 connected into their circuit even, thou single wire leads to each socket.'

The structure within the sock-A ing contact d@ best seen in Figure sheet metal and comprising two arme apart a distance slightly less than tn. the outside4 of a pair oi lampj cylindrical integral strip over a lowered portion of the we two sides of the socket recess i of the arcuate strip 52 is to provide for the spring arms and to serve the bridging contact in the soci;

i ro s and their 'ole in the front View, shown in Figure sectors spaced apart less than the or overlan by a sheet of insulation 5t one of which. is sho in detail in Figure 5 as suitably shaped Fill space between the contrai web r wall of the recess viii below the wings c i.

wall of the recess to prevent movement o toe insulation piece toward the curved lamp. body, but the concave portion ciently cut away to clear the recess The thickness of the bridging contact and its covering insulation sheets is not sufficient require any changes in the shape or size of the insulating body or the conventional individuati spring contacts therein, but the insulation sheets eectively serve to separate the bridging contact from the terminal contacts as seen in Figure When no lamp pins are in position the individual contacts il', it are insulated from each other so that the circuit will be open as explained in connection with Figure 6. When, however, a lamp .is positioned in the socket and rotated to engage itspins I2 and I3 with the contact springs II and I8 as shown in Figure 2, these pins will also engage the arms I 'of the bridging contact as also seen in that figure, thereby shunting the filament I4 and ensuring a continuous circuit from 44 tothe primaries 40 and4l. It likewise ensures that both ends of the filament will be at the same potential on the left side of the lamps Where but a single lead is arranged for each socket.

It will be appreciated that the device may be used as an attachment for sockets Without otherwise making any changes in their construction and that ii; may readily be removed where it is desired to operate lamps under the older system with starters landreactors.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. A socket for double-ended electric lamps l having two laterally disposed longitudinally extending contact pins at one end, comprising a member' of insulatingmaterial having in one .face thereof a recess arranged to rotatably accommodate said pins, said recess being connected to an edge of said member by a slot for l pin entrance, a pair of contactsin said member face thereof a recess arranged to rotatably accommodate said pins, said recess being connected to an edge of said member by a slot for pin entrance, a `pair of contacts in said member each constructed and positioned for engagement by one of said pins when rotated from entrance position, and a bridging contact in said member, Vpositioned to contact both pins when they are engaged by said pair of contacts.

3. A socket for double-ended electric lamps having .two parallel pins extending from one end', comprising a member of insulating material having a recess arranged to receive said pins, individual contacts for engaging said pins and for connection into a circuit, and a bridg-` ing contact insulated from said contacts and positioned to be engaged by both pins` to shunt said contacts when the 1am-p is in position.

`4. A socket for double-ended Aelectric lampshaving two terminals" at one end, comprising a member of insulation, a pair of contacts positioned thereon'fojr engagement each with one ot said terminals,.a bridging contact carried by said insulation separate from the pair, said bridging contact being constructed to engage both said terminals only when they are engaged by said pair of contacts.

5. A socket for use with double-ended electric 5 lamps having a base at one end tted lwith a pair of outwardly extending pins, comprising a body of insulation having a pin recess in one face thereof and a pin entrance slot extending from the recess to the edge of said face, individual spring contacts in said recess spaced to each separately engage one of said pins upon rotation of the lamp pins 90 from the plane of said slot, l.and means on said socket to electrically connect said pins together when in said last mentioned l5 position.

6. A socket for use with double-ended electric lamps having a base at one end fitted with a pair of outwardly extending pins, comprising a body of insulation having a pin recess in one face thereof and a pin entrance slot extending from the recess t0 thel edge of said face, individual spring contacts in said recess spaced to each separately engage one of said pins upon rotation of the lamp pins 90 from the plane of said slot, and spring means in said recess toelectrically engage and connect together said pins when in said last mentioned position.

'7. A socket for use with a double-ended tubular lamp having a base at each end tted with a pair of outwardly extending pins, al1 of which lie in a single plane, said socket having a face to confront one end of the lamp and having a pin recess and a pin entrance slot extending from the recess to the edge of said face, spring contacts in said recess spaced to engage the corresponding pins upon their rotation of 90 from the plane of said slot, and means carried by said socket to shunt said pins and to shunt said contacts therein only when the lamp is in said last 40 mentioned position.

.8. A bridging contact spring for use in a fluorescent lamp socket comprising a sheet metal member having arms spaced apart less than the distance between the outside surfaces of the pins on one end of a lamp, and an integral spring part joining said arms and being elevated out of the plane thereof.

9. For use with a conventional fluorescent lamp socket, associated parts comprising a bridging contact constructed to be received in the insulation body at the back of the front Wall and including a pair of electrically connected arms each positioned to be contacted by one ofthe pins of a lamp; and means insulating said, contact from the two socket contacts.

10. A lamp socket of the type described comprising a body of insulation, a pair of individual contacts, a bridging contact, means insulating each of said contacts from the others, saidconf tacts being so positioned that they are all connected together through the pin contacts of al lamp positioned in the socket.

MARK N. RUSSELL 

